Translation:It is important for each one to look around.
In this sentence it is because the verb is reflexive: guardarsi. It is used in sentences like 'to look at himself in the mirror' ='guardarsi nello specchio'. To look around 'guardarsi intorno' actually means 'to look around herself/himself' but in spoken English we often drop the 'oneself/himself/themselves etc'. Good dictionaries usually put the reflexive form of a verb (if there is one) at the end of the entry, and will give you examples of how they are used. Good luck - it will make sense after a while - honestly!